Formation of Infinite‐Layered (Ca_1‐xSr_x) CuO₂ and NaCuO₂‐type (Ca_1‐yNa_y)_0.85CuO₂ in Tartrate Route

Abstract

Both NaCuO2‐type Ca0.85CuO2 and infinite‐layered (Ca1‐xSrx)CuO2 could be prepared much more easily by firing the dried solids from mixed acetate aqueous solutions titrated with tartaric acid than by normal calcination. The presence of a narrow solid‐solution composition range of 0.10 < x > 0.16 was confirmed in infinite‐layered (Ca1‐xSrx)CuO2 in the preparation using the tartrate route. The calcium could also be substituted by sodium in a range of y > 0.15 in NaCuO2‐type (Ca1‐yNay)0.85CuO2 using the same route. Further substitution of Ca2+ with Y3+ might also be possible in infinite‐layered (Ca1‐xSrx)CuO2, but resulted in the NaCuO2‐type compound in the substitution with Na+.

Preparation of Transparent Conductive (ZnO)mIn2O3 Fine Powder by Gel‐Combustion Reaction

“…In an earlier study, we investigated the precipitation of crystalline oxide during the firing of a gel obtained from an aqueous solution of mixed metal salts. Both NaCuO 2 ‐type Ca 0.85 CuO 2 and infinitely layered (Ca 1− x Sr x )CuO 2 could be prepared at lower temperature by firing solids from mixed acetate aqueous solutions titrated with tartaric acid than by normal calcination of an oxide mixture 7 . The lower firing temperature was attained because of the homogeneity of the mixed acetates in the aqueous solution.…”

Phase diagrams for the YBa2Cu3O7 family — ANNO 1996

“…Detailed variation of the unit-cell parameters as a function of composition is shown in Ref. [188]. The discovery of this phase was given considerable attention, since its crystal structure contains only the infinite sheets of corner-shared squares as the copper oxygen coordinations, and was quickly dubbed "the parent structure of the high-To superconductors" (Eventually, the structure has been made superconducting by using high-pressure syntheses for doped versions: A p-type superconductor with Tc = 110 K is obtained by introducing AEvacancies [189], and an n-type superconductor by Nd-doping [190].).…”